跳躍比對式多重格網PIV質點影像分析法

A Jump Matching Scheme for the Multi-Grid Iterative PIV Analysis

木文中提出跳躍式的質點影像型態比對法，於應用多重格網分析PIV質點影像時，不必合併質點影像畫素為較大畫素、降低影像解析度，以獲得流場的速度預估值，而以跳躍數個畫素的方式，執行質點影像型態比對，即可獲得等同於合併畫素的運算結果。以此方法，可輕易的串連中央差分式的質點影像型態比對，質點影像內插，與質點影像變形法為一體，以大幅提高質點影像分析的空間解析度與量測精確度。文中先以具理論解的標準質點影像為例，證明跳躍式質點影像型態比對法的可行性，再以之分析流體通過雙並列圓柱的渦漩擺動流場。由所得量測結果可知，跳躍式的質點影像型態比對法確實可以簡易的方式，量測得複雜流場的速度分佈。 In this study, a jump matching scheme for the Particle Image Pattern Matching correlation is proposed. In the multi-grid, iterative particle image distortion analysis, the coarse grid solutions are not obtained by binning pixels, but by jumping the interrogation window the number of pixels specified during the particle image matching process. With the jump matching scheme implemented, the central difference particle image pattern matching, particle image interpolation, and image distortion analysis are easily linked together to resolve the flow field from coarsest grid to super-resolution grid. The proposed method is first verified by standard particle images of impinging jet flow that has exact solution available, and then applied to analyze uniform flow past two side-by-side circular cylinders. Satisfactory results are obtained from the jump matching scheme proposed.